Chuck-jaw.



0. PARPARTQ cHUcK'JAw.

APPLICATION FILED MAR. 16, 1908.

Patented June 22,1909.

THE NORRIS PETERS 10., "WASHINGTON n E UNITED s'ra'rns earner clerics.

OTTO IARIARJ, ()l CLEVELAND, UlllO.

CHUCICJ'AW.

To all whom it may concern:

Be it known that I, OTTO PARPAR'L, a citizen of the United States, andresident of Cleveland, in the county of Cuyahoga and State of Ohio, haveinvented certain new and useful Improvements in Chuck Jaws, of which Ihereby declare the following to be a full, clear, and exact description,such as will enable others skilled in the art to which it appertains tomake and use the same.

The invention relates to improvements in gripping jaws adapted for usewith twist drill, or analogous tool holding chucks, and the objects areto provide jaws of such a form as to be able to accurately center theshanks of the tools, and to exert a powerful pressure upon them, whenthe shanks are flat, without injury of any kind to the shank, and alsoto provide adjustable jaws of such a form as to adapt them to a varyingnumber of sizes of flat shanks.

Twist drills are ordinarily provided with cylindrical shanks, and othercutting tools such as taps and reamers with shanks that are partlycylindrical or ta. er, and partly flat. The shanks to which t 1e presentjaws are adapted however, are flattened throughout their length and jawsof ordinary form can not properly center them and obtain the requiredpurchase upon them without danger of rounding off the corners of theshanks or otherwise injuring them.

The invention further comprises the peculiar conformation of the jawswhereby they are capable of securely gripping and obtaining a purchaseupon variable sizes of flat shanks, and of accurately centering theshanks in the chuck, and in the construction of the various details, ashereinafter described, shown in the accompanying drawings, andspecifically pointed out in the claims.

In the accompanying drawings, Figure 1 is a plan or bottom view of thechuck showing the gri ping edges of the jaws and an opening in t e.cover through which the tool is inserted Fig. 2 is a side elevationthereof; Fig. 3 is a plan view of the jaws and chuck show ing the jawsadjusted to engage with a wide shank and Fig. 4 is a similar viewshowing theljaws adjusted to engage with a smaller too In these views 1is the body of the chuck, 2, 2 are diametrical grooves in the face ofthe chuck in which the jaws 3, 3, having exactly Specification ofLetters Patent.

Application filed March 16, 1908.

Patented June 22, 1909.

Serial No. 421,482.

parallel sides are movable toward and away from the axial line of thechuck. The right and left hand threaded screws 5 and 6 con nected bymeans of a central unthreaded portion 7 are employed to operate thejaws, and the female screw is located partly in the jaws and partly inthe clutch body as shown at 8 and 9 respectively, Fig. 2.

The twofold objects of adapting the inner and gripping faces of the jawsto securely engage with flat shanks of varying thickness and width andalso to present to the side of the shank a driving shoulder and surfacebroad enough to provide for a direct applica tion of pressure thereto,and so to prevent cutting away or twisting off the corner of the shankunder the strong torsional strain upon the drill, are accomplished asfollows; the gripping faces of the aws are diagonally inclined at anangle approximating, preferz'rbly, 63%, and the edges of each grippingface are stepped at 12, forming an angle with the inclined face ofapproximately 72%. The shoulder 12 is not formed centrally of the jawbut at a slight distance on one side of the center so that the spaceinclosed between the two shoulders when the jaws are closed will closelyapproximate the thickness of the smallest shank to be used, as shown inFig. 1. The inclined surfaces are therefore separated into two parts 10and 11 upon different planes, parallel to the axis of the chuck. Theshank will therefore lie diagonally in the jaws, and when the jaws areseparated as in Fig. 3 it will be seen that a wide shank of much greaterthickness can readily be inserted between and securely gripped by thejaws, and that the large shank will lie in them at substantially thesame angle as the smaller shank. The shoulders or offsets 12 alsoprovide broad bearing surfaces upon the driven sides of the shank, andwhen the pressure is brought to bear upon the drill the inclines 10 10,serve as wedges to force the shanks more tightly against the shoulders12.

The device is applicable to use with all rotatable tools having flatshanks, whether plain or centrally ribbed, since the engagement is madeby the shoulders only at the edges of the shanks.

The advantages of this form of aws, are obvious in their power toaccurately center the shank in the chuck, and also to obtain a definiteand positive purchase thereon.

Having described the invention what I claim as new and desire to secureby Letters Patent is 1. In a chuck adapted to hold flat shanks ofvarious sizes, oppositely moving jaws and engaging faces therein, saidfaces adapted for gripping and centering said shanks and comprisingopposite parallel faces inclined to the center line of the jaws adaptedto engage the edges of a shank, said faces provided with shoulders,spaced from each other on each side of the center line of said jaws,against which shoulders the sides of said shank are adapted to rest,said shoulders extending at an angle to the adjacent jaw faces.

2 In chuck jaws, adapted for centering and rotating a fiat shank, facestherefor parallel to each other in each jaw and inclined to the centerline of said jaws, said shoulders located on opposite sides of thecenter line of said jaws and spaced therefrom, said shoulders connectingsaid parallel faces in each jaw, and forming acute angles therewith, andthe shoulder in one j aw parallel with the shoulder in the other jaw.

3. In a chuck for centering and driving a flat shank, in combination,oppositely mov ing jaws, each jaw provided with flat, lon and shortfaces, said faces inclined relatively to the center line of the jaws andparallel to each other, the short face in one jaw being opposite to thelong face in the other jaw, and oppositely facing parallel shoulderslocated on opposite sides of said center line a shoulder arranged toconnect the inner edges of the said long and short planes in each aw,each shoulder outwardly inclined relatively to the said center line ofsaid jaws and spaced from said center line, thus providing a centralopening having inclined sides.

4. In a chuck for centering and driving a flat shank, in combination,diametrically and oppositely movable jaws, parallel centering faces forsaid jaws, inclined to the center line of said. jaws, said facesseparated into long and short portions, the short portion of one facebeing opposed to the long portion of the other face, and an inclineddriving shoulder connecting the inner edges of the long and short planesin each face, the said shoulders being located on opposite sides of thecenter line of said jaws, and parallel to each other, and spaced fromeach other, thus providing a central opening when the aws are closed,adapted to permit of the introduction of varying sized shanks when thejaws are opened.

5. In chuck jaws adapted for centering and rotating varying sizes offlat shanks, in combination with said jaws, opposite inclined facestherefor, adapted to engage the edges of said shanks and oppositeparallel inclined shoulders spaced laterally from the center line ofsaid jaws, and located on oppo site sides 9f the center line thereof,and adapted to engage the faces of said shanks, said inclined faces andshoulders forming the sides of a parallelogram inclined relatively tothe center line of said jaws.

In testimony whereof I hereunto set my hand this 6 day of March 1908.

OTTO PARPART.

In presence of E. B. NORTHWAY, WM. M. MONROE.

